1
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Islam R, Choudhary H, Rajan R, Vrionis F, Hanafy KA. An overview on microglial origin, distribution, and phenotype in Alzheimer's disease. J Cell Physiol 2024; 239:e30829. [PMID: 35822939 PMCID: PMC9837313 DOI: 10.1002/jcp.30829] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/12/2022] [Accepted: 07/04/2022] [Indexed: 01/17/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease that is responsible for about one-third of dementia cases worldwide. It is believed that AD is initiated with the deposition of Ab plaques in the brain. Genetic studies have shown that a high number of AD risk genes are expressed by microglia, the resident macrophages of brain. Common mode of action by microglia cells is neuroinflammation and phagocytosis. Moreover, it has been discovered that inflammatory marker levels are increased in AD patients. Recent studies advocate that neuroinflammation plays a major role in AD progression. Microglia have different activation profiles depending on the region of brain and stimuli. In different activation, profile microglia can generate either pro-inflammatory or anti-inflammatory responses. Microglia defend brain cells from pathogens and respond to injuries; also, microglia can lead to neuronal death along the way. In this review, we will bring the different roles played by microglia and microglia-related genes in the progression of AD.
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Affiliation(s)
- Rezwanul Islam
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
| | - Hadi Choudhary
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
| | - Robin Rajan
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
| | - Frank Vrionis
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
| | - Khalid A. Hanafy
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
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2
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Wheeler S, Rai-Bhogal R, Crawford DA. Abnormal Microglial Density and Morphology in the Brain of Cyclooxygenase 2 Knockin Mice. Neuroscience 2023; 534:66-81. [PMID: 37863307 DOI: 10.1016/j.neuroscience.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/22/2023]
Abstract
Prostaglandin E2 (PGE2) is a signaling molecule produced by cyclooxygenase-2 (COX-2) that is important in healthy brain development. Anomalies in the COX-2/PGE2 pathway due to genetic or environmental factors have been linked to Autism Spectrum Disorders (ASD). Our previous studies showed that COX-2 deficient (COX-2-KI) mice exhibit sex-dependent molecular changes in the brain and associated autism-related behaviors. Here, we aim to determine the effect of COX-2-KI on microglial density and morphology in the developing brain. Microglia normally transition between an amoeboid or ramified morphology depending on their surroundings and are important for the development of the healthy brain, assisting with synaptogenesis, synaptic pruning, and phagocytosis. We use COX-2-KI male and female mice to evaluate microglia density, morphology, and branch length and number in five brain regions (cerebellum, hippocampus, olfactory bulb, prefrontal cortex, and thalamus) at the gestational day 19 (G19) and postnatal day 25 (PN25). We discovered that COX2-KI females were affected at G19 with increased microglial density, altered percentage of amoeboid and ramified microglia, affected branch length, and decreased branching networks in a region-specific manner; these effects persisted to PN25 in select regions. Interestingly, while limited changes were found in G19 COX-2-KI males, at PN25 we found increased microglial density, higher percentages of ramified microglia, and increased branch counts, and length observed in nearly all brain regions tested. Overall, we show for the first time that the COX-2 deficiency in our ASD mouse model influences microglia morphology in a sex- and region- and stage-dependent manner.
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Affiliation(s)
- Sarah Wheeler
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada
| | | | - Dorota A Crawford
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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3
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Hopkins WD, Li X, Roberts N, Mulholland MM, Sherwood CC, Edler MK, Raghanti MA, Schapiro SJ. Age differences in cortical thickness and their association with cognition in chimpanzee (Pan troglodytes). Neurobiol Aging 2023; 126:91-102. [PMID: 36958104 PMCID: PMC10106435 DOI: 10.1016/j.neurobiolaging.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 02/16/2023] [Accepted: 02/18/2023] [Indexed: 02/24/2023]
Abstract
Humans and chimpanzees are genetically similar and share a number of life history, behavioral, cognitive and neuroanatomical similarities. Notwithstanding, our understanding of age-related changes in cognitive and motor functions in chimpanzees remains largely unstudied despite recent evident demonstrating that chimpanzees exhibit many of the same neuropathological features of Alzheimer's disease observed in human postmortem brains. Here, we examined age-related differences in cognition and cortical thickness measured from magnetic resonance images in a sample of 215 chimpanzees ranging in age between 9 and 54 years. We found that chimpanzees showed global and region-specific thinning of cortex with increasing age. Further, within the elderly cohort, chimpanzees that performed better than average had thicker cortex in frontal, temporal and parietal regions compared to chimpanzees that performed worse than average. Independent of age, we also found sex differences in cortical thickness in 4 brain regions. Males had higher adjusted cortical thickness scores for the caudal anterior cingulate, rostral anterior cingulate, and medial orbital frontal while females had higher values for the inferior parietal cortex. We found no evidence that increasing age nor sex was associated with asymmetries in cortical thickness. Moreover, age-related differences in cognitive function were only weakly associated with asymmetries in cortical thickness. In summary, as has been reported in humans and other primates, elderly chimpanzees show thinner cortex and variation in cortical thickness is associated with general cognitive functions.
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Affiliation(s)
- William D Hopkins
- National Center for Chimpanzee Care, Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, TX.
| | - Xiang Li
- School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
| | - Neil Roberts
- School of Clinical Sciences, University of Edinburgh, Edinburgh, UK
| | - Michele M Mulholland
- National Center for Chimpanzee Care, Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, TX
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC
| | - Melissa K Edler
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, OH
| | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, OH
| | - Steven J Schapiro
- National Center for Chimpanzee Care, Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, TX; Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
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4
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Edler MK, Munger EL, Maycon H, Hopkins WD, Hof PR, Sherwood CC, Raghanti MA. The association of astrogliosis and microglial activation with aging and Alzheimer's disease pathology in the chimpanzee brain. J Neurosci Res 2023; 101:881-900. [PMID: 36647571 DOI: 10.1002/jnr.25167] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/31/2022] [Accepted: 12/30/2022] [Indexed: 01/18/2023]
Abstract
Aging and neurodegenerative disorders, such as Alzheimer's disease (AD), trigger an immune response known as glial activation in the brain. Recent evidence indicates species differences in inflammatory responses to AD pathology, highlighting the need for additional comparative studies to further understand human-specific neuropathologies. In the present study, we report on the occurrence of astrogliosis, microglial activation, and their relationship with age and AD-like pathology in a cohort of male and female chimpanzees (Pan troglodytes). Chimpanzees with severe astrogliosis exhibited widespread upregulation of hypertrophic astrocytes immunoreactive for glial fibrillary acidic protein (GFAP) throughout all layers of the dorsolateral prefrontal cortex and a loss of the interlaminar palisade. In addition, extreme astrogliosis was associated with increased astrocyte density in the absence of significant microglial activation and AD lesions. A shift from decreased resting to increased phagocytotic microglia occurred with aging, although proliferation was absent and no changes in astrogliosis was observed. Vascular amyloid correlated with decreased astrocyte and microglia densities, while tau lesions were associated with morphological changes in microglia and greater total glia density and glia: neuron ratio. These results further our understanding of inflammatory processes within the chimpanzee brain and provide comparative data to improve our understanding of human aging and neuropathological processes.
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Affiliation(s)
- Melissa K Edler
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - Emily L Munger
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - Hannah Maycon
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - William D Hopkins
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, Texas, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA
| | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio, USA
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Rigby Dames BA, Kilili H, Charvet CJ, Díaz-Barba K, Proulx MJ, de Sousa AA, Urrutia AO. Evolutionary and genomic perspectives of brain aging and neurodegenerative diseases. PROGRESS IN BRAIN RESEARCH 2023; 275:165-215. [PMID: 36841568 PMCID: PMC11191546 DOI: 10.1016/bs.pbr.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This chapter utilizes genomic concepts and evolutionary perspectives to further understand the possible links between typical brain aging and neurodegenerative diseases, focusing on the two most prevalent of these: Alzheimer's disease and Parkinson's disease. Aging is the major risk factor for these neurodegenerative diseases. Researching the evolutionary and molecular underpinnings of aging helps to reveal elements of the typical aging process that leave individuals more vulnerable to neurodegenerative pathologies. Very little is known about the prevalence and susceptibility of neurodegenerative diseases in nonhuman species, as only a few individuals have been observed with these neuropathologies. However, several studies have investigated the evolution of lifespan, which is closely connected with brain size in mammals, and insights can be drawn from these to enrich our understanding of neurodegeneration. This chapter explores the relationship between the typical aging process and the events in neurodegeneration. First, we examined how age-related processes can increase susceptibility to neurodegenerative diseases. Second, we assessed to what extent neurodegeneration is an accelerated form of aging. We found that while at the phenotypic level both neurodegenerative diseases and the typical aging process share some characteristics, at the molecular level they show some distinctions in their profiles, such as variation in genes and gene expression. Furthermore, neurodegeneration of the brain is associated with an earlier onset of cellular, molecular, and structural age-related changes. In conclusion, a more integrative view of the aging process, both from a molecular and an evolutionary perspective, may increase our understanding of neurodegenerative diseases.
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Affiliation(s)
- Brier A Rigby Dames
- Department of Computer Science, University of Bath, Bath, United Kingdom; Department of Psychology, University of Bath, Bath, United Kingdom.
| | - Huseyin Kilili
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Christine J Charvet
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
| | - Karina Díaz-Barba
- Licenciatura en Ciencias Genómicas, UNAM, CP62210, Cuernavaca, México; Instituto de Ecología, UNAM, Ciudad Universitaria, CP04510, Ciudad de México, México
| | - Michael J Proulx
- Department of Psychology, University of Bath, Bath, United Kingdom
| | | | - Araxi O Urrutia
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom; Licenciatura en Ciencias Genómicas, UNAM, CP62210, Cuernavaca, México; Instituto de Ecología, UNAM, Ciudad Universitaria, CP04510, Ciudad de México, México.
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6
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Munger EL, Edler MK, Hopkins WD, Hof PR, Sherwood CC, Raghanti MA. Comparative analysis of astrocytes in the prefrontal cortex of primates: Insights into the evolution of human brain energetics. J Comp Neurol 2022; 530:3106-3125. [PMID: 35859531 PMCID: PMC9588662 DOI: 10.1002/cne.25387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 11/09/2022]
Abstract
Astrocytes are the main homeostatic cell of the brain involved in many processes related to cognition, immune response, and energy expenditure. It has been suggested that the distribution of astrocytes is associated with brain size, and that they are specialized in humans. To evaluate these, we quantified astrocyte density, soma volume, and total glia density in layer I and white matter in Brodmann's area 9 of humans, chimpanzees, baboons, and macaques. We found that layer I astrocyte density, soma volume, and ratio of astrocytes to total glia cells were highest in humans and increased with brain size. Overall glia density in layer I and white matter were relatively invariant across brain sizes, potentially due to their important metabolic functions on a per volume basis. We also quantified two transporters involved in metabolism through the astrocyte-neuron lactate shuttle, excitatory amino acid transporter 2 (EAAT2) and glucose transporter 1 (GLUT1). We expected these transporters would be increased in human brains due to their high rate of metabolic consumption and associated gene activity. While humans have higher EAAT2 cell density, GLUT1 vessel volume, and GLUT1 area fraction compared to baboons and chimpanzees, they did not differ from macaques. Therefore, EAAT2 and GLUT1 are not related to increased energetic demands of the human brain. Taken together, these data provide evidence that astrocytes play a unique role in both brain expansion and evolution among primates, with an emphasis on layer I astrocytes having a potentially significant role in human-specific metabolic processing and cognition.
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Affiliation(s)
- Emily L. Munger
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, OH
| | - Melissa K. Edler
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, OH
| | - William D. Hopkins
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
| | - Patrick R. Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
| | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, OH
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7
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Wei Y, Li X. Different phenotypes of microglia in animal models of Alzheimer disease. Immun Ageing 2022; 19:44. [PMID: 36209099 PMCID: PMC9547462 DOI: 10.1186/s12979-022-00300-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/19/2022] [Accepted: 09/19/2022] [Indexed: 11/10/2022]
Abstract
Microglia are immune-competent cells that are critically involved in maintaining normal brain function. A prominent characteristic of Alzheimer disease (AD) is microglial proliferation and activation concentrated around amyloid plaques in the brain. Recent research has revealed numerous microglial phenotypes related to aging and AD, apart from the traditional M1 and M2 types. Redox signalling modulates the acquisition of the classical or alternative microglia activation phenotypes. The numerous microglial functions can be achieved through these multiple phenotypes, which are associated with distinct molecular signatures.
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Affiliation(s)
- Yun Wei
- grid.464481.b0000 0004 4687 044XXiyuan Hospital of China Academy of Chinese Medical Sciences, 100091 Beijing, China
| | - Xianxiao Li
- Jingxi Cancer Hospital, 100161 Beijing, China
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8
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August I, Semendeferi K, Marchetto MC. Brain aging, Alzheimer's disease, and the role of stem cells in primate comparative studies. J Comp Neurol 2022; 530:2940-2953. [PMID: 35929189 DOI: 10.1002/cne.25394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/24/2022] [Accepted: 07/09/2022] [Indexed: 11/10/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is ultimately fatal. Currently, millions of Americans are living with AD, and this number is predicted to grow with increases in the aging population. Interestingly, despite the prevalence of AD in human populations, the full AD phenotype has not been observed in any nonhuman primate (NHP) species, and it has been suggested that NHPs are immune to neurodegenerative diseases such as AD. Here, we review the typical age-related changes and pathologies in humans along with the neuropathologic changes associated with AD, and we place this information in the context of the comparative neuropathology of NHPs. We further propose the use of induced pluripotent stem cell technology as a way of addressing initial molecular processes and changes that occur in neurons and glia (in both humans and NHPs) when exposed to AD-inducing pathology prior to cell death.
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Affiliation(s)
- Isabel August
- Department of Anthropology, University of California, San Diego, San Diego, California, USA
| | - Katerina Semendeferi
- Department of Anthropology, University of California, San Diego, San Diego, California, USA.,Center for Academic Research and Training in Anthropogeny (CARTA), San Diego, California, USA
| | - Maria Carolina Marchetto
- Department of Anthropology, University of California, San Diego, San Diego, California, USA.,Center for Academic Research and Training in Anthropogeny (CARTA), San Diego, California, USA
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Španić E, Langer Horvat L, Ilić K, Hof PR, Šimić G. NLRP1 Inflammasome Activation in the Hippocampal Formation in Alzheimer's Disease: Correlation with Neuropathological Changes and Unbiasedly Estimated Neuronal Loss. Cells 2022; 11:2223. [PMID: 35883667 PMCID: PMC9324749 DOI: 10.3390/cells11142223] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/12/2022] [Accepted: 07/16/2022] [Indexed: 02/04/2023] Open
Abstract
Neuroinflammation is one of the core pathological features of Alzheimer's disease (AD) as both amyloid β (Aβ) and tau monomers and oligomers can trigger the long-term pro-inflammatory phenotype of microglial cells with consequent overactivation of the inflammasomes. To investigate the NLRP1 inflammasome activation in AD, we analyzed the expression of NLRP1, ASC, cleaved gasdermin (cGSDMD), and active caspase-6 (CASP-6) proteins in each hippocampal subdivision (hilar part of CA3, CA2/3, CA1, subiculum) of postmortem tissue of 9 cognitively healthy controls (HC) and 11 AD patients whose disease duration varied from 3 to 7 years after the clinical diagnosis. The total number of neurons, along with the total number of neurofibrillary tangles (NFTs), were estimated in Nissl- and adjacent modified Bielschowsky-stained sections, respectively, using the optical disector method. The same 9 HC and 11 AD cases were additionally semiquantitatively analyzed for expression of IBA1, HLA-DR, and CD68 microglial markers. Our results show that the expression of NLRP1, ASC, and CASP-6 is present in a significantly greater number of hippocampal formation neurons in AD brains compared to controls, suggesting that the NLRP1 inflammasome is more active in the AD brain. None of the investigated inflammasome and microglial markers were found to correlate with the age of the subjects or the duration of AD. However, besides positive correlations with microglial IBA1 expression in the subiculum and with microglial CD68 expression in the CA1 field and subiculum in the AD group, the overall NLRP1 expression in the hippocampal formation was positively correlated with the number of NFTs, thus providing a causal link between neuroinflammation and neurofibrillary degeneration. The accumulation of AT8-immunoreactive phosphorylated tau proteins that we observed at nuclear pores of large pyramidal neurons of the Ammon's horn further supports their role in the extent of neuronal dysfunction and degeneration in AD. This is important because unlike fibrillar amyloid-β deposits that are not related to dementia severity, total NFTs and neuron numbers in the hippocampal formation, especially in the CA1 field, are the best correlates of cognitive deterioration in both human brain aging and AD. Our findings also support the notion that the CA2 field vulnerability is strongly linked to specific susceptibilities to different tauopathies, including primary age-related tauopathy. Altogether, these findings contrast with reports of nonsignificant microglial activation in aged nonhuman primates and indicate that susceptibility to inflammasome activation may render the human brain comparatively more vulnerable to neurodegenerative changes and AD. In conclusion, our results confirm a key role of NLRP1 inflammasome in AD pathogenesis and suggest NLRP1 as a potential diagnostic marker and therapeutic target to slow or prevent AD progression.
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Affiliation(s)
- Ena Španić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
| | - Lea Langer Horvat
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
| | - Katarina Ilić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
- BRAIN Centre, Institute of Psychiatry, Psychology, and Neuroscience, King’s College London, London WC2R 2LS, UK
| | - Patrick R. Hof
- Nash Family Department of Neuroscience, Friedman Brain Institute, and Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Goran Šimić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
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10
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Shippy DC, Ulland TK. Exploring the zinc-related transcriptional landscape in Alzheimer’s disease. IBRO Neurosci Rep 2022; 13:31-37. [PMID: 35711243 PMCID: PMC9193853 DOI: 10.1016/j.ibneur.2022.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/13/2022] [Accepted: 06/04/2022] [Indexed: 11/01/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurological disorder, and increasing evidence suggests AD pathology is driven by metabolic dysfunction in the brain. Zinc is the second most abundant trace element found in the human body and is required by all living organisms. Zinc is used extensively in many biological processes, and alterations in zinc levels are implicated in the pathogenesis of numerous diseases, including AD. Since small fluctuations in brain zinc levels appear to effect AD progression, we investigated the zinc-related transcriptional responses in an AD versus non-AD state using microarray and RNA-sequencing (RNA-seq) datasets from cultured cells, mice, and humans. We identified 582 zinc-related differentially expressed genes (DEG) in human dorsolateral prefrontal cortex samples of late-onset AD (LOAD) versus non-AD controls, 146 zinc-related DEG in 5XFAD versus wild-type mice, and 95 zinc-related DEG in lipopolysaccharide (LPS)-stimulated N9 microglia versus unstimulated control cells, with 19 zinc-related DEG common to all three datasets. Of the 19 common DEG, functional enrichment and network analyses identified several biological processes and molecular functions, such as mRNA destabilization and nucleic acid binding, which may be important in neuroinflammation and AD development. Furthermore, therapeutic drugs targeting zinc-related DEG in the human dataset were identified. Taken together, these data provide insights into zinc utilization for gene transcription during AD progression which may further our understanding of AD pathogenesis and could identify new targets for therapeutic strategies targeted towards AD. Transcriptome analyses of AD versus non-AD from cultured cells, mice, and humans. Nineteen differentially expressed zinc-related genes common to all three datasets. Zinc-related DEGs could represent new therapeutic targets for AD.
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11
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Xu YJ, Au NPB, Ma CHE. Functional and Phenotypic Diversity of Microglia: Implication for Microglia-Based Therapies for Alzheimer’s Disease. Front Aging Neurosci 2022; 14:896852. [PMID: 35693341 PMCID: PMC9178186 DOI: 10.3389/fnagi.2022.896852] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/05/2022] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease and is closely associated with the accumulation of β-amyloid (Aβ) and neurofibrillary tangles (NFTs). Apart from Aβ and NFT pathologies, AD patients also exhibit a widespread microglial activation in various brain regions with elevated production of pro-inflammatory cytokines, a phenomenon known as neuroinflammation. In healthy central nervous system, microglia adopt ramified, “surveying” phenotype with compact cell bodies and elongated processes. In AD, the presence of pathogenic proteins such as extracellular Aβ plaques and hyperphosphorylated tau, induce the transformation of ramified microglia into amoeboid microglia. Ameboid microglia are highly phagocytic immune cells and actively secrete a cascade of pro-inflammatory cytokines and chemokines. However, the phagocytic ability of microglia gradually declines with age, and thus the clearance of pathogenic proteins becomes highly ineffective, leading to the accumulation of Aβ plaques and hyperphosphorylated tau in the aging brain. The accumulation of pathogenic proteins further augments the neuroinflammatory responses and sustains the activation of microglia. The excessive production of pro-inflammatory cytokines induces a massive loss of functional synapses and neurons, further worsening the disease condition of AD. More recently, the identification of a subset of microglia by transcriptomic studies, namely disease-associated microglia (DAM), the progressive transition from homeostatic microglia to DAM is TREM2-dependent and the homeostatic microglia gradually acquire the state of DAM during the disease progression of AD. Recent in-depth transcriptomic analysis identifies ApoE and Trem2 from microglia as the major risk factors for AD pathogenesis. In this review, we summarize current understandings of the functional roles of age-dependent microglial activation and neuroinflammation in the pathogenesis of AD. To this end, the exponential growth in transcriptomic data provides a solid foundation for in silico drug screening and gains further insight into the development of microglia-based therapeutic interventions for AD.
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Affiliation(s)
- Yi-Jun Xu
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Ngan Pan Bennett Au
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Chi Him Eddie Ma
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- *Correspondence: Chi Him Eddie Ma,
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12
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Edler MK, Mhatre-Winters I, Richardson JR. Microglia in Aging and Alzheimer's Disease: A Comparative Species Review. Cells 2021; 10:1138. [PMID: 34066847 PMCID: PMC8150617 DOI: 10.3390/cells10051138] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
Microglia are the primary immune cells of the central nervous system that help nourish and support neurons, clear debris, and respond to foreign stimuli. Greatly impacted by their environment, microglia go through rapid changes in cell shape, gene expression, and functional behavior during states of infection, trauma, and neurodegeneration. Aging also has a profound effect on microglia, leading to chronic inflammation and an increase in the brain's susceptibility to neurodegenerative processes that occur in Alzheimer's disease. Despite the scientific community's growing knowledge in the field of neuroinflammation, the overall success rate of drug treatment for age-related and neurodegenerative diseases remains incredibly low. Potential reasons for the lack of translation from animal models to the clinic include the use of a single species model, an assumption of similarity in humans, and ignoring contradictory data or information from other species. To aid in the selection of validated and predictive animal models and to bridge the translational gap, this review evaluates similarities and differences among species in microglial activation and density, morphology and phenotype, cytokine expression, phagocytosis, and production of oxidative species in aging and Alzheimer's disease.
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Affiliation(s)
- Melissa K. Edler
- Department of Anthropology, School of Biomedical Sciences, Brain Health Research Institute, Kent State University, Kent, OH 44240, USA;
| | - Isha Mhatre-Winters
- School of Biomedical Sciences, College of Arts and Sciences, Kent State University, Kent, OH 44240, USA;
- Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Jason R. Richardson
- Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
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13
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Mulholland MM, Sherwood CC, Schapiro SJ, Raghanti MA, Hopkins WD. Age- and cognition-related differences in the gray matter volume of the chimpanzee brain (Pan troglodytes): A voxel-based morphometry and conjunction analysis. Am J Primatol 2021; 83:e23264. [PMID: 33899958 DOI: 10.1002/ajp.23264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/29/2021] [Accepted: 04/10/2021] [Indexed: 01/01/2023]
Abstract
Several primate species have been shown to exhibit age-related changes in cognition, brain, and behavior. However, severe neurodegenerative illnesses, such as Alzheimer's disease (AD), were once thought to be uniquely human. Recently, some chimpanzees naturally were documented to develop both neurofibrillary tangles and amyloid plaques, the main characteristics of AD pathology. In addition, like humans and other primates, chimpanzees show similar declines in cognition and motor function with age. Here, we used voxel-based morphometry to examine the relationships among gray matter volume, age, and cognition using magnetic resonance imaging scans previously acquired from chimpanzees (N = 216). We first determined the relationship between age and gray matter volume, identifying the regions that declined with age. With a subset of our sample (N = 103), we also determined differences in gray matter volume between older chimpanzees with higher cognition scores than expected for their age, and older chimpanzees with lower than expected scores. Finally, we ran a conjunction analysis to determine any overlap in brain regions between these two analyses. We found that as chimpanzees age, they lose gray matter in regions associated with cognition. In addition, cognitively healthy older chimpanzees (those performing better for their age) have greater gray matter volume in many brain regions compared with chimpanzees who underperform for their age. Finally, the conjunction analysis revealed that regions of age-related decline overlap with the regions that differ between cognitively healthy chimpanzees and those who underperform. This study provides further evidence that chimpanzees are an important model for research on the neurobiology of aging. Future studies should investigate the effects of cognitive stimulation on both cognitive performance and brain structure in aging nonhuman primates.
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Affiliation(s)
- Michele M Mulholland
- Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, Texas, USA
| | - Chet C Sherwood
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington DC, USA
| | - Steven J Schapiro
- Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, Texas, USA.,Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - William D Hopkins
- Department of Comparative Medicine, The University of Texas MD Anderson Cancer Center, Bastrop, Texas, USA
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14
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Ovsepian SV, O'Leary VB, Hoschl C, Zaborszky L. Integrated phylogeny of the human brain and pathobiology of Alzheimer's disease: A unifying hypothesis. Neurosci Lett 2021; 755:135895. [PMID: 33862141 DOI: 10.1016/j.neulet.2021.135895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 02/08/2023]
Abstract
The disproportionate evolutionary expansion of the human cerebral cortex with reinforcement of cholinergic innervations warranted a major rise in the functional and metabolic load of the conserved basal forebrain (BF) cholinergic system. Given that acetylcholine (ACh) regulates properties of the microtubule-associated protein (MAP) tau and promotes non-amyloidogenic processing of amyloid precursor protein (APP), growing neocortex predicts higher demands for ACh, while the emerging role of BF cholinergic projections in Aβ clearance infers greater exposure of source neurons and their innervation fields to amyloid pathology. The higher exposure of evolutionary most recent cortical areas to the amyloid pathology of Alzheimer's disease (AD) with synaptic impairments and atrophy, therefore, might involve attenuated homeostatic effects of BF cholinergic projections, in addition to fall-outs of inherent processes of expanding association areas. This unifying model, thus, views amyloid pathology and loss of cholinergic cells as a quid pro quo of the allometric evolution of the human brain, which in combination with increase in life expectancy overwhelm the fine homeostatic balance and trigger the disease process.
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Affiliation(s)
- Saak V Ovsepian
- Department of Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic.
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Ruská 87, 100 00, Praha 10, Czech Republic
| | - Cyril Hoschl
- Department of Experimental Neurobiology, National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic; Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Ruská 87, 100 00, Prague 10, Czech Republic
| | - Laszlo Zaborszky
- Center for Molecular and Behavioral Neuroscience, Rutgers, the State University of New Jersey, Newark, NJ, USA
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15
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Doust YV, King AE, Ziebell JM. Implications for microglial sex differences in tau-related neurodegenerative diseases. Neurobiol Aging 2021; 105:340-348. [PMID: 34174592 DOI: 10.1016/j.neurobiolaging.2021.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 11/26/2022]
Abstract
Tauopathies are a group of neurodegenerative diseases that involve pathological changes to the tau protein. Neuroinflammation is a commonly reported feature of tauopathies that has been demonstrated to exacerbate tau pathology and, hence, neurodegeneration. Microglia can mediate the inflammatory response in order to maintain brain homeostasis. In the aged brain, microglia are reported to undergo morphological and functional changes, adopting a pro-inflammatory profile and loss of homeostatic functions. Dystrophic and dysfunctional microglia are associated with tau pathology in the healthy and diseased brain which is proposed to contribute to disease development and progression. Microglia have also been recently demonstrated to possess sexually dimorphic roles in the developing, adult and aged brain. The sex differences in microglial functionality suggest that microglia may contribute to tauopathies which may differ between sexes. This review highlights the detrimental loop between age-related microglial changes and tau pathology with implications for microglial sexual dichotomy.
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Affiliation(s)
- Yasmine V Doust
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Jenna M Ziebell
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia.
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16
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Hopkins WD, Mareno MC, Webb SJN, Schapiro SJ, Raghanti MA, Sherwood CC. Age-related changes in chimpanzee (Pan troglodytes) cognition: Cross-sectional and longitudinal analyses. Am J Primatol 2021; 83:e23214. [PMID: 33169860 PMCID: PMC7904603 DOI: 10.1002/ajp.23214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/17/2020] [Accepted: 10/25/2020] [Indexed: 01/06/2023]
Abstract
Chimpanzees are the species most closely related to humans, yet age-related changes in brain and cognition remain poorly understood. The lack of studies on age-related changes in cognition in chimpanzees is particularly unfortunate in light of the recent evidence demonstrating that this species naturally develops Alzheimer's disease (AD) neuropathology. Here, we tested 213 young, middle-aged, and elderly captive chimpanzees on the primate cognitive test battery (PCTB), a set of 13 tasks that assess physical and social cognition in nonhuman primates. A subset of these chimpanzees (n = 146) was tested a second time on a portion of the PCTB tasks as a means of evaluating longitudinal changes in cognition. Cross-sectional analyses revealed a significant quadratic association between age and cognition with younger and older chimpanzees performing more poorly than middle-aged individuals. Longitudinal analyses showed that the oldest chimpanzees at the time of the first test showed the greatest decline in cognition, although the effect was mild. The collective data show that chimpanzees, like other nonhuman primates, show age-related decline in cognition. Further investigations into whether the observed cognitive decline is associated with AD pathologies in chimpanzees would be invaluable in understanding the comparative biology of aging and neuropathology in primates.
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Affiliation(s)
- William D Hopkins
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
| | - Mary Catherine Mareno
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
| | - Sarah J Neal Webb
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
| | - Steven J Schapiro
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
- Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute Kent State University, Kent, Ohio 44242, USA
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
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17
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Shahidehpour RK, Higdon RE, Crawford NG, Neltner JH, Ighodaro ET, Patel E, Price D, Nelson PT, Bachstetter AD. Dystrophic microglia are associated with neurodegenerative disease and not healthy aging in the human brain. Neurobiol Aging 2021; 99:19-27. [PMID: 33422891 PMCID: PMC8293930 DOI: 10.1016/j.neurobiolaging.2020.12.003] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/31/2020] [Accepted: 12/02/2020] [Indexed: 01/26/2023]
Abstract
Loss of physiological microglial function may increase the propagation of neurodegenerative diseases. Cellular senescence is a hallmark of aging; thus, we hypothesized age could be a cause of dystrophic microglia. Stereological counts were performed for total microglia, 2 microglia morphologies (hypertrophic and dystrophic) across the human lifespan. An age-associated increase in the number of dystrophic microglia was found in the hippocampus and frontal cortex. However, the increase in dystrophic microglia was proportional to the age-related increase in the total number of microglia. Thus, aging alone does not explain the presence of dystrophic microglia. We next tested if dystrophic microglia could be a disease-associated microglia morphology. Compared with controls, the number of dystrophic microglia was greater in cases with either Alzheimer's disease, dementia with Lewy bodies, or limbic-predominant age-related TDP-43 encephalopathy. These results demonstrate that microglia dystrophy, and not hypertrophic microglia, are the disease-associated microglia morphology. Finally, we found strong evidence for iron homeostasis changes in dystrophic microglia, providing a possible molecular mechanism driving the degeneration of microglia in neurodegenerative disease.
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Affiliation(s)
- Ryan K Shahidehpour
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Rebecca E Higdon
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Nicole G Crawford
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Janna H Neltner
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pathology and Laboratory Medicine, Division of Neuropathology, University of Kentucky, Lexington, KY, USA
| | - Eseosa T Ighodaro
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Ela Patel
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Douglas Price
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Peter T Nelson
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pathology and Laboratory Medicine, Division of Neuropathology, University of Kentucky, Lexington, KY, USA
| | - Adam D Bachstetter
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
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18
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Giordano KR, Denman CR, Dubisch PS, Akhter M, Lifshitz J. An update on the rod microglia variant in experimental and clinical brain injury and disease. Brain Commun 2021; 3:fcaa227. [PMID: 33501429 PMCID: PMC7811762 DOI: 10.1093/braincomms/fcaa227] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022] Open
Abstract
Contemporary microglia morphologies include ramified, activated and amoeboid, with the morphology of microglia considered highly coupled to the cellular function. Rod microglia are an additional activated microglia variant observed in the ageing, injured and diseased brain. Rod microglia were reported frequently in the early 1900s by neuropathologists in post-mortem cases of general paresis, Alzheimer's disease and encephalitis, and then remained largely ignored for almost 100 years. Recent reports have renewed interest in rod microglia, most notably after experimental traumatic brain injury. Rod microglia are formed by the narrowing of the soma and retraction of planar processes, which results in the appearance of an elongated, rod-shaped cell. Rod microglia are most commonly observed in the cortex, aligned perpendicular to the dural surface and adjacent to neuronal processes; in the hippocampus, they are aligned perpendicular to hippocampal layers. Furthermore, rod microglia form trains with one another, apical end to basal end. By replicating the process of sketching microscopic observation, rod microglia are re-defined by circumnutation around the long axis. In this update, we summarize the rod microglia variant in clinical and experimental literature and advocate for investigation into mechanisms of rod microglia origin and function.
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Affiliation(s)
- Katherine R Giordano
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, USA.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Charlotte R Denman
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA.,Department of Biology and Biochemistry, University of Bath, Bath, UK
| | | | - Murtaza Akhter
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, USA.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA.,Department of Emergency Medicine, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA.,Maricopa Integrated Healthcare System, Phoenix, AZ, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ, USA.,Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA.,Phoenix VA Health Care System, Phoenix, AZ, USA
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19
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Edler MK, Munger EL, Meindl RS, Hopkins WD, Ely JJ, Erwin JM, Mufson EJ, Hof PR, Sherwood CC, Raghanti MA. Neuron loss associated with age but not Alzheimer's disease pathology in the chimpanzee brain. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190619. [PMID: 32951541 PMCID: PMC7540958 DOI: 10.1098/rstb.2019.0619] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2020] [Indexed: 12/25/2022] Open
Abstract
In the absence of disease, ageing in the human brain is accompanied by mild cognitive dysfunction, gradual volumetric atrophy, a lack of significant cell loss, moderate neuroinflammation, and an increase in the amyloid beta (Aβ) and tau proteins. Conversely, pathologic age-related conditions, particularly Alzheimer's disease (AD), result in extensive neocortical and hippocampal atrophy, neuron death, substantial Aβ plaque and tau-associated neurofibrillary tangle pathologies, glial activation and severe cognitive decline. Humans are considered uniquely susceptible to neurodegenerative disorders, although recent studies have revealed Aβ and tau pathology in non-human primate brains. Here, we investigate the effect of age and AD-like pathology on cell density in a large sample of postmortem chimpanzee brains (n = 28, ages 12-62 years). Using a stereologic, unbiased design, we quantified neuron density, glia density and glia:neuron ratio in the dorsolateral prefrontal cortex, middle temporal gyrus, and CA1 and CA3 hippocampal subfields. Ageing was associated with decreased CA1 and CA3 neuron densities, while AD pathologies were not correlated with changes in neuron or glia densities. Differing from cerebral ageing and AD in humans, these data indicate that chimpanzees exhibit regional neuron loss with ageing but appear protected from the severe cell death found in AD. This article is part of the theme issue 'Evolution of the primate ageing process'.
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Affiliation(s)
- Melissa K. Edler
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Anthropology, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
| | - Emily L. Munger
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Anthropology, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
| | - Richard S. Meindl
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Anthropology, Kent State University, Kent, OH 44242, USA
| | - William D. Hopkins
- Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | | | - Joseph M. Erwin
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052, USA
| | - Elliott J. Mufson
- Departments of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Patrick R. Hof
- Nash Family Department of Neuroscience, Ronald M. Loeb Center for Alzheimer's Disease, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- New York Consortium for Evolutionary Primatology, New York, NY 10468, USA
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052, USA
| | - Mary Ann Raghanti
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
- Department of Anthropology, Kent State University, Kent, OH 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
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20
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Rogers Flattery CN, Rosen RF, Farberg AS, Dooyema JM, Hof PR, Sherwood CC, Walker LC, Preuss TM. Quantification of neurons in the hippocampal formation of chimpanzees: comparison to rhesus monkeys and humans. Brain Struct Funct 2020; 225:2521-2531. [PMID: 32909100 DOI: 10.1007/s00429-020-02139-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/29/2020] [Indexed: 12/15/2022]
Abstract
The hippocampal formation is important for higher brain functions such as spatial navigation and the consolidation of memory, and it contributes to abilities thought to be uniquely human, yet little is known about how the human hippocampal formation compares to that of our closest living relatives, the chimpanzees. To gain insight into the comparative organization of the hippocampal formation in catarrhine primates, we quantified neurons stereologically in its major subdivisions-the granular layer of the dentate gyrus, CA4, CA2-3, CA1, and the subiculum-in archival brain tissue from six chimpanzees ranging from 29 to 43 years of age. We also sought evidence of Aβ deposition and hyperphosphorylated tau in the hippocampus and adjacent neocortex. A 42-year-old animal had moderate cerebral Aβ-amyloid angiopathy and tauopathy, but Aβ was absent and tauopathy was minimal in the others. Quantitatively, granule cells of the dentate gyrus were most numerous, followed by CA1, subiculum, CA4, and CA2-3. In the context of prior investigations of rhesus monkeys and humans, our findings indicate that, in the hippocampal formation as a whole, the proportions of neurons in CA1 and the subiculum progressively increase, and the proportion of dentate granule cells decreases, from rhesus monkeys to chimpanzees to humans. Because CA1 and the subiculum engender key hippocampal projection pathways to the neocortex, and because the neocortex varies in volume and anatomical organization among these species, these findings suggest that differences in the proportions of neurons in hippocampal subregions of catarrhine primates may be linked to neocortical evolution.
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Affiliation(s)
| | - Rebecca F Rosen
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20814, USA
| | - Aaron S Farberg
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, 30329, USA
| | - Jeromy M Dooyema
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, 30329, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, 20052, USA
| | - Lary C Walker
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, 30329, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Todd M Preuss
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, 30329, USA.,Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
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21
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Xu M, Zhang L, Liu G, Jiang N, Zhou W, Zhang Y. Pathological Changes in Alzheimer's Disease Analyzed Using Induced Pluripotent Stem Cell-Derived Human Microglia-Like Cells. J Alzheimers Dis 2020; 67:357-368. [PMID: 30562902 DOI: 10.3233/jad-180722] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microglia constitute the majority of innate immune cells in the brain, and their dysfunction is associated with various central nervous system diseases. Human microglia are extremely difficult to obtain experimentally, thereby limiting studies on their role in complex diseases. Microglia derived from human stem cells provide new tools to assess the pathogenesis of complex diseases and to develop effective treatment methods. This study aimed to develop a reliable method to derive human microglial-like cells (iMGLs) from induced pluripotent stem cells (iPSCs) expressing microglia-specific markers IBA1 and TMEM119 and respond to lipopolysaccharide (LPS) stimulation. Thereafter, we compared iMGL functions from Alzheimer's disease (AD) patients and cognitive normal controls (CNCs). AD-iMGLs displayed stronger phagocytic ability with or without stimulation. High LPS concentrations (>2μg/ml) caused death in CNC-iMGLs, while AD-iMGLs did not display significant cell death. Cytokine analysis revealed that TNF-α, IL-6, and IL-10 secreted by AD-iMGLs were significantly increased upon LPS stimulation compared to those in CNC-iMGLs. The present results indicate that AD-iMGLs exhibit significant inflammatory characteristics and can reflect some pathological changes in microglia in AD, thereby providing new valuable tools to screen candidate drugs for AD and to elucidate the mechanisms underlying AD pathogenesis.
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Affiliation(s)
- Mei Xu
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
| | - Lin Zhang
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
| | - Gang Liu
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
| | - Ning Jiang
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
| | - Wenxia Zhou
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
| | - Yongxiang Zhang
- Beijing Institute of Pharmacology and Toxicology, Beijing, P.R. China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing, P.R. China
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22
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Fossel M. A unified model of dementias and age-related neurodegeneration. Alzheimers Dement 2020; 16:365-383. [PMID: 31943780 DOI: 10.1002/alz.12012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/09/2019] [Accepted: 11/25/2019] [Indexed: 12/14/2022]
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23
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Nose-to-brain co-delivery of repurposed simvastatin and BDNF synergistically attenuates LPS-induced neuroinflammation. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2019; 23:102107. [PMID: 31655202 DOI: 10.1016/j.nano.2019.102107] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/16/2019] [Accepted: 10/01/2019] [Indexed: 12/29/2022]
Abstract
A therapeutic strategy that can combat the multifaceted nature of neuroinflammation pathology was investigated. Thus, we fabricated PEG-PdLLA polymersomes and evaluated the efficacy in co-delivery of simvastatin (Sim, as a repurposed anti-inflammatory agent) with brain derived neurotrophic factor (BDNF, as an exogeneous trophic factor supplementation). Using LPS model of neuroinflammation, intranasal administration of combination drug-loaded polymersomes (containing both Sim and BDNF; Sim-BDNF-Ps) markedly down-regulated brain levels of cytokines compared to free drug and single-drug-loaded polymersomes. Further, Sim-BDNF-Ps effectively replenished brain level of BDNF that was depleted following neuroinflammation, resulting in a 2-fold BDNF increase versus untreated LPS control group. We found out that the efficiency of the combination drug-loaded polymersomes to suppress microglia activation in brain regions followed the order: frontal cortex > striatum > hippocampus. Our findings indicated that Sim-BDNF-Ps could effectively inhibit microglial-mediated inflammation as well as potentially resolve the neurotoxic microenvironment that is often associated with neuroinflammation.
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24
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Manickavasagam D, Oyewumi MO. Internalization of particulate delivery systems by activated microglia influenced the therapeutic efficacy of simvastatin repurposing for neuroinflammation. Int J Pharm 2019; 570:118690. [DOI: 10.1016/j.ijpharm.2019.118690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/03/2019] [Accepted: 09/08/2019] [Indexed: 10/26/2022]
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25
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Krachun C, Lurz R, Mahovetz LM, Hopkins WD. Mirror self-recognition and its relationship to social cognition in chimpanzees. Anim Cogn 2019; 22:1171-1183. [PMID: 31542841 DOI: 10.1007/s10071-019-01309-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 09/03/2019] [Accepted: 09/13/2019] [Indexed: 12/23/2022]
Abstract
Chimpanzees and humans are capable of recognizing their own reflection in mirrors. Little is understood about the selective pressures that led to this evolved trait and about the mechanisms that underlie it. Here, we investigated the hypothesis that mirror self-recognition in chimpanzees is the byproduct of a developed form of self-awareness that was naturally selected for its adaptive use in social cognitive behaviors. We present here the first direct attempt to assess the social cognition hypothesis by analyzing the association between mirror self-recognition in chimpanzees, as measured by a mirror-mark test, and their performance on a variety of social cognition tests. Consistent with the social cognition hypothesis, chimpanzees who showed evidence of mirror self-recognition in the mark test tended to perform significantly better on the social cognition tasks than those who failed the mark test. Additionally, the data as a whole fit the social cognition hypothesis better than the main competing hypothesis of mirror self-recognition in great apes, the secondary representation hypothesis. Our findings strongly suggest that the evolutionary origins of great apes' and humans' capacity to understand ourselves, as revealed by our capacity to recognize ourselves in mirrors, are intimately linked to our ability to understand others.
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Affiliation(s)
- Carla Krachun
- Department of Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK, Canada.
| | - Robert Lurz
- Department of Philosophy, Brooklyn College, CUNY, 2900 Bedford Avenue, Brooklyn, NY, USA
| | - Lindsay M Mahovetz
- Department of Psychology, University of North Florida, 1 UNF Drive, Jacksonville, FL, USA
| | - William D Hopkins
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX, USA
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Munger EL, Edler MK, Hopkins WD, Ely JJ, Erwin JM, Perl DP, Mufson EJ, Hof PR, Sherwood CC, Raghanti MA. Astrocytic changes with aging and Alzheimer's disease-type pathology in chimpanzees. J Comp Neurol 2019; 527:1179-1195. [PMID: 30578640 PMCID: PMC6401278 DOI: 10.1002/cne.24610] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/20/2018] [Accepted: 12/01/2018] [Indexed: 01/01/2023]
Abstract
Astrocytes are the main homeostatic cell of the central nervous system. In addition, astrocytes mediate an inflammatory response when reactive to injury or disease known as astrogliosis. Astrogliosis is marked by an increased expression of glial fibrillary acidic protein (GFAP) and cellular hypertrophy. Some degree of astrogliosis is associated with normal aging and degenerative conditions such as Alzheimer's disease (AD) and other dementing illnesses in humans. The recent observation of pathological markers of AD (amyloid plaques and neurofibrillary tangles) in aged chimpanzee brains provided an opportunity to examine the relationships among aging, AD-type pathology, and astrocyte activation in our closest living relatives. Stereologic methods were used to quantify GFAP-immunoreactive astrocyte density and soma volume in layers I, III, and V of the prefrontal and middle temporal cortex, as well as in hippocampal fields CA1 and CA3. We found that the patterns of astrocyte activation in the aged chimpanzee brain are distinct from humans. GFAP expression does not increase with age in chimpanzees, possibly indicative of lower oxidative stress loads. Similar to humans, chimpanzee layer I astrocytes in the prefrontal cortex are susceptible to AD-like changes. Both prefrontal cortex layer I and hippocampal astrocytes exhibit a high degree of astrogliosis that is positively correlated with accumulation of amyloid beta and tau proteins. However, unlike humans, chimpanzees do not display astrogliosis in other cortical layers. These results demonstrate a unique pattern of cortical aging in chimpanzees and suggest that inflammatory processes may differ between humans and chimpanzees in response to pathology.
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Affiliation(s)
- Emily L. Munger
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Melissa K. Edler
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio,Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - William D. Hopkins
- Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, Georgia
| | | | - Joseph M. Erwin
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia
| | - Daniel P. Perl
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Elliott J. Mufson
- Departments of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York,New York Consortium in Evolutionary Primatology, New York, New York
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
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